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  <title>PHPCrawl webcrawler library for PHP - Requirements</title>
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        <h1 style="margin: 0px; float: left;">PHPCrawl webcrawler library/framework</h1>
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        <h3>Resume aborted crawling-processes</h3><br />
        Sometimes it may happen that a crawling-process (or a script thats using phpcrawl) gets aborted/terminated
        while spidering a website before it was finished completely (for whatever reasons).<br /><br />
        
        Since PHPCrawl 0.81 it is possible to resume such a terminated script/process from the point where it was
        halted (so it's not necessary to restart the script all over again).<br /><br />
        
        In order to be able to resume a crawling-process, you'll have to
        <ul>
          <li>Initially call the <a href="classreferences/PHPCrawler/method_detail_tpl_method_enableResumption.htm" target="blank">enableResumption()</a> method in your script (from the first start, this prepares the crawler for possible 
              resumption and is necessary to be able to resume the script later on)<br />
          </li>
          
          <li>
          Determinate the unique crawler-ID by calling <a href="classreferences/PHPCrawler/method_detail_tpl_method_getCrawlerId.htm" target="blank">getCrawlerId()</a> and store it somewhere (this ID is needed for identifying the process that should be resumed later on)<br />
          <p id="code">
            </span><span style="color: #FF8000">//&nbsp;...
            <br /></span><span style="color: #0000BB">$crawler&nbsp;</span><span style="color: #007700">=&nbsp;new&nbsp;</span><span style="color: #0000BB">MyCrawler</span><span style="color: #007700">();
            <br /></span><span style="color: #0000BB">$crawler</span><span style="color: #007700">-&gt;</span><span style="color: #0000BB">setURL</span><span style="color: #007700">(</span><span style="color: #DD0000">"www.anyurl.com"</span><span style="color: #007700">);
            <br /></span><span style="color: #0000BB">$crawler</span><span style="color: #007700">-&gt;</span><span style="color: #0000BB">enableResumption</span><span style="color: #007700">();

            <br />
            <br /></span><span style="color: #0000BB">$ID&nbsp;</span><span style="color: #007700">=&nbsp;</span><span style="color: #0000BB">$crawler</span><span style="color: #007700">-&gt;</span><span style="color: #0000BB">getCrawlerId</span><span style="color: #007700">();
            <br /></span><span style="color: #FF8000">//&nbsp;...
            <br /></span><span style="color: #0000BB">?&gt;</span>
            </span>
          </p>
          </li>
        </ul>
        
        In order to resume an aborted process, you'll have to
        <ul>
          <li>Call the <a href="classreferences/PHPCrawler/method_detail_tpl_method_resume.htm" target="blank">resume()</a>-method before calling the go() or goMultiProcessed() method and pass the crawler-ID of the terminated crawling-process
              you want to resume to it (as returned by <a href="classreferences/PHPCrawler/method_detail_tpl_method_getCrawlerId.htm" target="blank">getCrawlerId()</a>)<br />
           <p id="code">  
           <span style="color: #FF8000">//&nbsp;...
           <br /></span><span style="color: #0000BB">$crawler</span><span style="color: #007700">-&gt;</span><span style="color: #0000BB">resume</span><span style="color: #007700">(</span><span style="color: #0000BB">120912912109</span><span style="color: #007700">);&nbsp;</span><span style="color: #FF8000">//ID&nbsp;of&nbsp;the&nbsp;aborted&nbsp;process

           <br /></span><span style="color: #0000BB">$crawler</span><span style="color: #007700">-&gt;</span><span style="color: #0000BB">goMultiProcessed</span><span style="color: #007700">(</span><span style="color: #0000BB">5</span><span style="color: #007700">);
           <br /></span><span style="color: #FF8000">//&nbsp;...
           <br /></span>
           <p/>
           </li>
        </ul>
        
        The following listing is a complete example of a resumable crawler-script (it's also included in the phpcrawl package).
        You may test it by starting it from the commandline (CLI, type "php resumable_example.php"), abort it (Ctrl^C) and start it again).
        
        <p id="code" style="width: 570px">
        <span style="color: #000000">
        <span style="color: #0000BB">&lt;?php
        <br />&nbsp;&nbsp;&nbsp;
        <br /></span><span style="color: #FF8000">//&nbsp;Inculde&nbsp;the&nbsp;phpcrawl-mainclass
        <br /></span><span style="color: #007700">include(</span><span style="color: #DD0000">"libs/PHPCrawler.class.php"</span><span style="color: #007700">);
        <br />
        <br /></span><span style="color: #FF8000">//&nbsp;Extend&nbsp;the&nbsp;class&nbsp;and&nbsp;override&nbsp;the&nbsp;handleDocumentInfo()-method&nbsp;

        <br /></span><span style="color: #007700">class&nbsp;</span><span style="color: #0000BB">MyCrawler&nbsp;</span><span style="color: #007700">extends&nbsp;</span><span style="color: #0000BB">PHPCrawler&nbsp;
        <br /></span><span style="color: #007700">{
        <br />&nbsp;&nbsp;function&nbsp;</span><span style="color: #0000BB">handleDocumentInfo</span><span style="color: #007700">(</span><span style="color: #0000BB">$DocInfo</span><span style="color: #007700">)&nbsp;
        <br />&nbsp;&nbsp;{
        <br />&nbsp;&nbsp;&nbsp;&nbsp;</span><span style="color: #FF8000">//&nbsp;Just&nbsp;detect&nbsp;linebreak&nbsp;for&nbsp;output

        <br />&nbsp;&nbsp;&nbsp;&nbsp;</span><span style="color: #007700">if&nbsp;(</span><span style="color: #0000BB">PHP_SAPI&nbsp;</span><span style="color: #007700">==&nbsp;</span><span style="color: #DD0000">"cli"</span><span style="color: #007700">)&nbsp;</span><span style="color: #0000BB">$lb&nbsp;</span><span style="color: #007700">=&nbsp;</span><span style="color: #DD0000">"\n"</span><span style="color: #007700">;
        <br />&nbsp;&nbsp;&nbsp;&nbsp;else&nbsp;</span><span style="color: #0000BB">$lb&nbsp;</span><span style="color: #007700">=&nbsp;</span><span style="color: #DD0000">"&lt;br&nbsp;/&gt;"</span><span style="color: #007700">;

        <br />
        <br />&nbsp;&nbsp;&nbsp;&nbsp;</span><span style="color: #FF8000">//&nbsp;Print&nbsp;the&nbsp;URL
        <br />&nbsp;&nbsp;&nbsp;&nbsp;</span><span style="color: #007700">echo&nbsp;</span><span style="color: #DD0000">"Page&nbsp;requested:&nbsp;"</span><span style="color: #007700">.</span><span style="color: #0000BB">$DocInfo</span><span style="color: #007700">-&gt;</span><span style="color: #0000BB">url</span><span style="color: #007700">.</span><span style="color: #0000BB">$lb</span><span style="color: #007700">;
        <br />&nbsp;&nbsp;&nbsp;&nbsp;</span><span style="color: #0000BB">flush</span><span style="color: #007700">();

        <br />&nbsp;&nbsp;}&nbsp;
        <br />}
        <br />
        <br /></span><span style="color: #0000BB">$crawler&nbsp;</span><span style="color: #007700">=&nbsp;new&nbsp;</span><span style="color: #0000BB">MyCrawler</span><span style="color: #007700">();
        <br /></span><span style="color: #0000BB">$crawler</span><span style="color: #007700">-&gt;</span><span style="color: #0000BB">setURL</span><span style="color: #007700">(</span><span style="color: #DD0000">"www.php.net"</span><span style="color: #007700">);
        <br /></span><span style="color: #0000BB">$crawler</span><span style="color: #007700">-&gt;</span><span style="color: #0000BB">addContentTypeReceiveRule</span><span style="color: #007700">(</span><span style="color: #DD0000">"#text/html#"</span><span style="color: #007700">);

        <br /></span><span style="color: #0000BB">$crawler</span><span style="color: #007700">-&gt;</span><span style="color: #0000BB">addURLFilterRule</span><span style="color: #007700">(</span><span style="color: #DD0000">"#\.(jpg|jpeg|gif|png)$#&nbsp;i"</span><span style="color: #007700">);
        <br /></span><span style="color: #0000BB">$crawler</span><span style="color: #007700">-&gt;</span><span style="color: #0000BB">setPageLimit</span><span style="color: #007700">(</span><span style="color: #0000BB">50</span><span style="color: #007700">);&nbsp;</span><span style="color: #FF8000">//&nbsp;Set&nbsp;page-limit&nbsp;to&nbsp;50&nbsp;for&nbsp;testing

        <br />
        <br />//&nbsp;Important&nbsp;for&nbsp;resumable&nbsp;scripts/processes!
        <br /></span><span style="color: #0000BB">$crawler</span><span style="color: #007700">-&gt;</span><span style="color: #0000BB">enableResumption</span><span style="color: #007700">();
        <br />
        <br /></span><span style="color: #FF8000">//&nbsp;At&nbsp;the&nbsp;firts&nbsp;start&nbsp;of&nbsp;the&nbsp;script&nbsp;retreive&nbsp;the&nbsp;crawler-ID

        <br />//&nbsp;and&nbsp;store&nbsp;it
        <br />//&nbsp;(in&nbsp;a&nbsp;temporary&nbsp;file&nbsp;in&nbsp;this&nbsp;example)
        <br /></span><span style="color: #007700">if&nbsp;(!</span><span style="color: #0000BB">file_exists</span><span style="color: #007700">(</span><span style="color: #DD0000">"/tmp/mycrawlerid_for_php.net.tmp"</span><span style="color: #007700">))

        <br />{
        <br />&nbsp;&nbsp;</span><span style="color: #0000BB">$crawler_ID&nbsp;</span><span style="color: #007700">=&nbsp;</span><span style="color: #0000BB">$crawler</span><span style="color: #007700">-&gt;</span><span style="color: #0000BB">getCrawlerId</span><span style="color: #007700">();
        <br />&nbsp;&nbsp;</span><span style="color: #0000BB">file_put_contents</span><span style="color: #007700">(</span><span style="color: #DD0000">"/tmp/mycrawlerid_for_php.net.tmp"</span><span style="color: #007700">,&nbsp;</span><span style="color: #0000BB">$crawler_ID</span><span style="color: #007700">);
        <br />}
        <br /></span><span style="color: #FF8000">//&nbsp;If&nbsp;the&nbsp;script&nbsp;was&nbsp;restarted&nbsp;again&nbsp;(after&nbsp;it&nbsp;was&nbsp;aborted),

        <br />//&nbsp;read&nbsp;the&nbsp;crawler-ID&nbsp;and&nbsp;pass&nbsp;it&nbsp;to&nbsp;the&nbsp;resume()&nbsp;method.
        <br /></span><span style="color: #007700">else
        <br />{
        <br />&nbsp;&nbsp;</span><span style="color: #0000BB">$crawler_ID&nbsp;</span><span style="color: #007700">=&nbsp;</span><span style="color: #0000BB">file_get_contents</span><span style="color: #007700">(</span><span style="color: #DD0000">"/tmp/mycrawlerid_for_php.net.tmp"</span><span style="color: #007700">);

        <br />&nbsp;&nbsp;</span><span style="color: #0000BB">$crawler</span><span style="color: #007700">-&gt;</span><span style="color: #0000BB">resume</span><span style="color: #007700">(</span><span style="color: #0000BB">$crawler_ID</span><span style="color: #007700">);
        <br />}
        <br />
        <br /></span><span style="color: #FF8000">//&nbsp;Start&nbsp;crawling
        <br /></span><span style="color: #0000BB">$crawler</span><span style="color: #007700">-&gt;</span><span style="color: #0000BB">goMultiProcessed</span><span style="color: #007700">(</span><span style="color: #0000BB">5</span><span style="color: #007700">);

        <br />
        <br /></span><span style="color: #FF8000">//&nbsp;Delete&nbsp;the&nbsp;stored&nbsp;crawler-ID&nbsp;after&nbsp;the&nbsp;process&nbsp;is&nbsp;finished
        <br />//&nbsp;completely&nbsp;and&nbsp;successfully.
        <br /></span><span style="color: #0000BB">unlink</span><span style="color: #007700">(</span><span style="color: #DD0000">"/tmp/mycrawlerid_for_php.net.tmp"</span><span style="color: #007700">);

        <br />
        <br /></span><span style="color: #0000BB">$report&nbsp;</span><span style="color: #007700">=&nbsp;</span><span style="color: #0000BB">$crawler</span><span style="color: #007700">-&gt;</span><span style="color: #0000BB">getProcessReport</span><span style="color: #007700">();
        <br />
        <br />if&nbsp;(</span><span style="color: #0000BB">PHP_SAPI&nbsp;</span><span style="color: #007700">==&nbsp;</span><span style="color: #DD0000">"cli"</span><span style="color: #007700">)&nbsp;</span><span style="color: #0000BB">$lb&nbsp;</span><span style="color: #007700">=&nbsp;</span><span style="color: #DD0000">"\n"</span><span style="color: #007700">;

        <br />else&nbsp;</span><span style="color: #0000BB">$lb&nbsp;</span><span style="color: #007700">=&nbsp;</span><span style="color: #DD0000">"&lt;br&nbsp;/&gt;"</span><span style="color: #007700">;
        <br />&nbsp;&nbsp;&nbsp;&nbsp;
        <br />echo&nbsp;</span><span style="color: #DD0000">"Summary:"</span><span style="color: #007700">.</span><span style="color: #0000BB">$lb</span><span style="color: #007700">;
        <br />echo&nbsp;</span><span style="color: #DD0000">"Links&nbsp;followed:&nbsp;"</span><span style="color: #007700">.</span><span style="color: #0000BB">$report</span><span style="color: #007700">-&gt;</span><span style="color: #0000BB">links_followed</span><span style="color: #007700">.</span><span style="color: #0000BB">$lb</span><span style="color: #007700">;

        <br />echo&nbsp;</span><span style="color: #DD0000">"Documents&nbsp;received:&nbsp;"</span><span style="color: #007700">.</span><span style="color: #0000BB">$report</span><span style="color: #007700">-&gt;</span><span style="color: #0000BB">files_received</span><span style="color: #007700">.</span><span style="color: #0000BB">$lb</span><span style="color: #007700">;
        <br />echo&nbsp;</span><span style="color: #DD0000">"Bytes&nbsp;received:&nbsp;"</span><span style="color: #007700">.</span><span style="color: #0000BB">$report</span><span style="color: #007700">-&gt;</span><span style="color: #0000BB">bytes_received</span><span style="color: #007700">.</span><span style="color: #DD0000">"&nbsp;bytes"</span><span style="color: #007700">.</span><span style="color: #0000BB">$lb</span><span style="color: #007700">;

        <br />echo&nbsp;</span><span style="color: #DD0000">"Process&nbsp;runtime:&nbsp;"</span><span style="color: #007700">.</span><span style="color: #0000BB">$report</span><span style="color: #007700">-&gt;</span><span style="color: #0000BB">process_runtime</span><span style="color: #007700">.</span><span style="color: #DD0000">"&nbsp;sec"</span><span style="color: #007700">.</span><span style="color: #0000BB">$lb</span><span style="color: #007700">;&nbsp;
        <br /></span><span style="color: #0000BB">?&gt;</span>&nbsp;</span>

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